Method of construction subways



Nov. 3, 1936.

W. CACCIA METHOD OF GONSTRUCTING SUBWAYS Filed April 3, 1936 5 Sheets-Sheet l INVENTOR WW mum,

ATTOR N EY Nov. 3, 1936. w. CACCIA METHOD OF CONSTRUCTING SUBWAYS 5 Sheets-Shet 2 Filed April 5, 1936 INVENTOR g3 CCLCM BY Q f/ R M.

ATTO RNEY Nov. 3, 1936.

w. CACCIA 2,059,774

I METHOD OF GONSTRUCTING SUBWAYS Filed April 3, 1956 5 Sheets-Sheet 3 N g a I'xTTORNEY Nov. 3, 1936. w. CACCIA 2,059,774

METHOD OF CONSTRUCTING SUBWAYS Fild April 3, 1956 5 Sheets-Sheet 4 ATTORNEY NOV. 3, 1936. w cAcc 2,059,774

METHOD OF CONSTRUCTING SUBWAYS Filed April 5, 1936 5 Sheets-Sheet 5 III/III INVENTOR ATTORNEY ,Patentecl Nov. 3, 1936 PATENT OFFICE METHOD OF CONSTRUCTING sUBwAYs Walter Caccia, White Plains, N. Y., assignor to John H. Unlandherm, New York, N. Y.

Application April 3, 1936, Serial No. 72,567

, 20 Claims.

This invention relates to the construction for and the method of supporting an existing supersurface or sub-surface structure, during and after the construction of a sub-surface structure, in rock excavation, where said new construction undermines or endangers said existing structure.

For the purpose of illustrating the invention, I haveselected the building of a subway (underground railroad) beneath anexisting elevated railroad structure, but it is to be understood that the invention extends beyond this mere applica-- tion.

Explaining, however, the invention in this particular application itjis pointed out that elevated structures such as are used forelevated railroads are generally located in the busy streets of large cities. tures are usually supported upon steel columns which are disposed transversely of the structure in pairs. .Each transverse pair of columns is usually referred to as a bent and the structure. longitudinally between the succeeding bents,

is usually referred to as a bay. Each of said. columns is provided with a masonry footing below the street surface which, where practicable, is carried to a sound rock foundation. It is also the practice to provide each column with a wheel guard which is placedaround said column at the street surface.

When a subway is to be constructed in a street,

- beneath such an existing elevated railroad structure, it will readily be understood that said elevated railroad structure must be supported during the entire life of the newconstruction work.

supported in such a manner as to maintain it,

at all times, in perfect alignmentjandgrade. T00

great care cannot be exercised .for the safety and maintenance of such a structure. Also, upon the completion of ,the subway the supports of the elevated railroad must be restored or equivalent supports furnished so as to leave the existing structure in as good and safe condition as it was at the beginning of the work.

The usual practlce'of subway construction is by the method known as cut and cover; that is to say, the excavation for the subway. structure is begun at the street surface and carried downwardly by the usual open-cut or trench methods but, before the excavation is permitted to proceed more than is absolutely necessary, a substantial temporary street decking structure is required to be installed capable of carrying the usual street traflic, both pedestrian and vehicu- Such. elevated railroad struc- 'lar. After said street decking is all in place the general excavation and subway construction may proceed, all work being prosecuted beneath said decking while street trafiic is fully maintained upon said decking.

It will now'be seen that in prosecuting this new subway construction, it will be necessary not only to support the existing elevated railroad structure, as previously described, but also to support the temporary street decking system. In the past, it has been the practice to employ a system of posts, needles, bracing and blocking, composed of a timber and steel and sometimes masonry, for the supportof the existing elevated railroad structure and a similar system of supports for the street decking. By numerous shiftings or changing of position of these supports and lengthening and extending them as required, they were carried downward progressively with the several stages 'or levels of the excavation work for the new subway. With this method of supporting the elevated railroad structure and the street ,decking, it is evident that all during the prosecution of the general excavation work there is always serious danger of said supports failing. Every time these supports are relocated or extended, which must be done to accommodate the work, there is risk of settlement or slipping;

especially where rock excavation is being done,

there is very serious danger of-dislodging these supports because of the shock of blasting or the sometimes uncontrollable movement or slide of rock following ablast.

The problem is further complicated by the existence, below the street surface, of numerous service structures such as watermains (both high and low pressure), gas mains, sewers, electric ducts, and sometimes-steam mains and mailing tubes. "I'hesef of course, must also, be carefully and safely maintained'so as not to interfere with their normal use. In some cases, similar posting and bracing, as-was above described, have been employed" tov supporflthse services, but 1 is always present the danger of serious accidents whenever these supports are relocated or extended as the work progresses. Still another and serious objection to this system is the fact that these supports and bracing are so numerous and complicated that they almost completely fill the working area within the cut so that hardly room enough remains for prosecuting the excavation work and the construction of the subway structure.

The safe support and maintenance of the elevated railroad structure and the like, and also every step.

Mainly because the methods for doing this work have not been improved beyond that briefly outlined above, it may be stated that subway construction in the streets of large cities still remains a very diificult and hazardous undertaking, very costly and requiring an unreasonably long and costly time for the completion of such pro- J'ects.

The present invention contemplates the safe and positive support of an existing structure such as an elevated railroad, which is over a new construction, such as a subway, during the entire life of the new construction work, by providing new temporary supports which shall be extended vertically downwardly into a sound foundation which shall be located such a distance below the bottom or lowermost level of the new construction work so as not to be endangered or disturbed by said new construction work.

The temporary supports shall be installed and the existing elevated railroad picked-up and supported thereon, prior to and independent of the excavation for the new subway adjacent the particular points where the supports are to. be located.

The temporary supports shall be provided, within the zone of rock or other excavation, with an envelope or casing which shall be filled with sand or a similar shock absorbing element, which shall completely surround'said temporary support for the purpose of protecting it against injury from blasting operations.

The temporary supports shall be provided with a system of structural steel bracing which shall be installed in a fixed position so as to provide the required stiffness and stability for the temporary supports and which shall not interfere with the construction of the new subway and shall remain in place until the completion of said subway.

When thesubway is about completed, the temporary supports shall be provided with seats or bases at about the level of the roof of the subway so that the load of the existing elevated railroad may be carried by the' upper portions of said temporary supports and said bases and delivered to the roof of the subway. Thus the upper portion of said temporary support is converted into a new permanent support for said existing elevated railroad, and the lower portion of the temporary support, below the roof of the new subway and within the subway excavation, is cut off and removed.

This invention further contemplates, in association with the temporary supports and bracing for the existing elevated railroad as above defined, similar, additional s'upports, similarly installed as to time and method, together with a system of steel girders and beams and timber flooring, to provide a temporary street decking for the maintenance of normal street traflic thereon.

This invention further contemplates, since the above defined temporary street decking is a positive system fixed in position and to remain in place undisturbed during the entire life of the new construction work, that the temporary decking system shall be designed for and employed to support the existing water mains, sewers, and the like, by suspending the same from the underside of the temporary decking system.

The foregoing brief outline clearly shows that this present invention is a great improvement over all present methods; that the entire system contemplated by this invention, makes possible the scientific design and detailing of all its parts, in the engineering ofiice; that the structural elements can be fabricated in the shops and shipped to the site ready for installation; that its installation is all accomplished separately from and in advance of the new subway construction work; that when it is installed it remains undisturbed during the entire life of the subway work; that it will offer a minimum of interference to the prosecution of the new subway construction; that it practically eliminates all uncertainty and risk and being properly designed and wisely installed will represent a minimum initial and maintenance cost and also have a large salvage or re-use value.

Summing up, therefore, the present invention will remove the uncertainty and risk from subway construction and reduce it to, simply, a construction job with the time and the cost of doing this work greatly reduced. It will be realized that certain phases of this invention are peculiarly adapted for use when the new or proposed excavation is to be made in rock and that other phases of the invention are applicable, as well,

Figures 1 to 9 inclusive, illustrate the progressive steps of the operations of the method of this invention and also the construction employed,

Figure 10 is a sectional view on line Ill-l0 of Figure 6,

Figure 11 is a fragmentary perspective view of the supporting columns and decking supports,

Figure 12 is a vertical sectional view disclosing the manner in which the columns are supported, finally, on the subway roof,

Figure 13 is a vertical sectional view taken at right angles to Figure 12,

Figure 14 is a horizontal sectional view on line "-44 of Figure 12, and

Figure 15 is a view of modified method of supporting the lower ends of the columns in the pits.

I have. shown, in the drawings, a typical case of the construction of a subway in rock excavaties and rails, upon which the trains are operated. This structure is, at the present time, supported upon columns 3 to which the girders I are connected as are also the transverse floor beams 2 which arearranged opposite the column points. These columns are disposed in transverse pairs, quite uniiormally along the length of the elevated structure. The columns 3 are each provided with a masonry footing 4 .which rests upon the top of rock 5. Around each column, at the street surface I, a wheel guard 8 is provided. There is also a layer of earth 6 which usually overlies the top of rock. I have thus shown and described an existing, typical elevated railroad structure and its present means of support.

Beneath the existing elevated railroad struc- ,ture a new subway is to be constructed. Its roof is designated 35, its sidewalls 350., its bottom or invert 35b. The under side of the invert, that is,

the bottom-most level of the subway structure is referred to as the subgrade and is designated 350. The conditions that are usually prescribed for a new subway construction are as follows:

The new subway shall be constructed by the "cut and cover method, which method is hereinbefore described. The existing elevated railroad structure shall be safely supported and maintained in good operating condition during entire life of the new subway work and when the subway is completed and the supports of the existing elevated railroad structure shall be restored to a condition equally as good as that which existed at the beginning of the work.

It is here pointed out that it is the primary purpose of this invention to provide a system of temporary supports for the existing railroad structure which shall be installed and the existing structure supported thereon in advance of commencing the general excavation for the subway and that said temporary supports shall stand, as initially installed, until converted as permanent supports upon the completed portion of the ad- Jacent subway; all of which shall conform with the prescribed conditions, as outlined above, for

the new subway work and the support, mainverse bracing to form rigid towers. Two of such towers are to be considered as a working unit-and are set up in the adjoining bays either side of the "bent" that is to be treated. It should be noted here that the bent is preferably to be treated as a unit, that is to say, the two existing columns or supports at the fbent are to be treated at the same time or in one operation.

These false work towers are given a foundation upon timbering Ma which rests upon the roadway pavement and the whole is firmly anchored in place. Between the tops .of these towers and the under sides of the floor beams 2, blocking, wedging andclamps H are provided. It will be noted that ,these towers do not extend beneath the floor vided for the support of the floor beams at the bent" point. i

Having thus set up the portable false work towers as just described, I have but to wedge-up at points Hi and II to support the existing superstructure upon the towers. In this manner I relieve the existingsupports (two adjacent columns) of their present load and may now remove them and proceed to installthe new columns of the new temporary system.

The wheel guards 8' are first removed, next, the earth 6 surrounding the footings 6 is excavated to the top of rock and this excavation is sheeted and braced at 9-H] in the usual manner. It is to be noted that the wheel guard and the earth surrounding the footing may, if desired, be removed prior to the placing of the falsework as shown in Figures 1 and 2. Next, the columns 3 are disconnected from the super-structure and the footing removed and finally, by drilling and blasting or otherwise, the masonry footings t i are removed as shown in Figure 3.

Directly in a vertical line with the columns just removed, I now excavate pits l8, by drilling and blasting or by any other acceptable method, which pits are carried vertically downward to such a depth as to bring their bottoms several feet below the sub-grade 350 of the new subway that later is to be constructed or in other words. deep enough to reach a zone out of danger of shock from blasting. (See Figure 3.) In practice these pits will have an average cross-sectional dimension of 42 inches or more if required, and be of any cross sectional configuration. At the bottom of the pits, holes are drilled vertically downward into which anchor bolts l9 are set and grouted firmly in place. These anchor bolts are provided with threads and nuts 20 at their upper ends (see Figure 4) I The pits it are now ready to receive the new columns or temporary supports for the existing elevated railroad structure. The temporary supports are designated 3 to distinguish them from the existing supports 3, one in each pit and firmly anchor each at its base it by means of the anchor bolts 69 (see Figure 4).

Next, I connect-up the existing super-structure to the top of the temporary support, using the same means of connections as were employed on the original supports, which have now been removed and replaced by said new temporary supports. It will now be seen that the foundations orbases 2! of the new temporary supports .3 are set, at the bottom of said pits. The purpose of this, it will of course be understood, is to locate said foundations of said temporary supports out of all danger from subsequent blasting and construction operations and also, where they can remain undisturbed until the completion of the subway work (see Figures 4, 5, 6, 7, 8).

I next provide a casing 26 of relatively thin metal or other suitable material, preferably of circular cross-sectionand of as large diameter as possible and yet permit its being conveniently lowered into the pits l8 and set concentrically around the temporary supports 3'. This may be made in transverse and longitudinal sections to facilitate its placing and removal. This casing is placed in the pit and made to extend from the bottom of the pit to within a short distance of the top of rock. It is wedged or otherwise held so as to stand concentrically around the temporary support. The purpose of this casing is to provide a tight container or envelope which I now.

proceed to fill to its top with sand or any other similar shock absorbing material 25. This material completely surrounds the temporary support within the zone of the subsequent rock excavation for the subway and is disposed in the manner indicated, for the purpose of absorbing any shock of subsequent blasting operations in the vicinity of said temporary support, and otherwise to effectively protect and brace the columns during the subway construction work.

The function of the casing 24, as mentioned above, is to provide a tight envelope for the sand cushion so that the sand shall be held in place until. the blasting is completed all around the column or longer if desired. In this connection it is pointed out that, in excavating the rock around the temporary support, the rock will naturally break away in uneven levels and therefore, there will be times when the rock has been removed from one side of the pit l8 to a lower level than on the other side (see Figures 7 and 8). In such cases, if it were not for said tight envelope the sand would run away at the low side and the temporary support would lose this protection as far as the removal of the high rock is concerned. However, with the casing 24 in place the sand 25 is retained and that side of said casing that has been exposed can be braced with timbering 32 in order that the sand cushion shall remain effective for the remainder of the blasting at this location.

In Figures 1 to 9 inclusive I have illustrated the footing of each of the columns 3 as being set in concrete which fills the pit to approximately the sub-grade of the new subway but if desired this concrete may be omitted and a construction such as illustrated in Figure 15 used in lieu thereof. In this construction the concrete is omitted and the casing'24 extended to the bottom of the pit and filled with the sand or other shock absorbing material.

The system of temporary supports contemplated by the present invention, comprises, not only the elements above described, but also longitudinal and transverse structural steel bracing 26 and 21 respectively, whereby said system of temporary supports is given the required stiffness and stability. Said longitudinal and transverse bracing may be installed at this stage of the operation but this can be done better and more economically at a later stage. Therefore, I have provided a temporary bracing 23, of timber or steel or both, which I place within the pit l8 near the top of rock and wedge same between the walls of the pit and the temporary support in order to obtain the required lateral bracing or stifiness for the temporary supports. This will remain in place until the above mentioned structural bracing is installed.

Summing up the foregoing it will be seen that I have treated one bent of the existing elevated structure by completely removing the two existing columns or supports at this point and substituted therefor two new temporary supports which are so proportioned-and braced as to safely carry the existing super-structure and so protected as to be fully safe-guarded against injury from the subsequent blasting and subway construction work. Having thus safely supported the existing elevated structure at this bent the false work towers may. now be removed and shifted forward and the above described operations repeated until the entire existing elevated structure has been similarly safely supported.

The foregoing operations have not thus far involved any subway construction work. This is as was intended, it being one of the objects of this invention, as previously stated, that the temporary supports for the existing elevated structure shall be installed prior to and independent of the subway construction work. This having been accomplished as outlined above,

we may now proceed with the subway construction work.

It should be explained here that if the temporary supports 3 are installed far in advance, say several weeks or even months, of the subway work, then the earth pits around said temporary supports could be back filled, the sheeting and bracing 9 and I0 removed and the street pavement temporarily restored. This would be an altogether practical procedure if it were desired so to do. In such a case, it is pointed out, the temporary supports are capable of standing indefinitely and also, the temporary supports above the street surface will offer no greater obstruction to traffic than did the original supports which they replace.

The subway construction work begins' with the I At this stage of the operations, preferably the previously mentioned longitudinal and trans-' verse bracing 26 and 21 is installed. This bracing consists of heavy structural steel beams or girders extending between the temporary supports and bolted or otherwise secured thereto.

This bracing, as shown on the drawings, is located in a level plane above the rock and below the street surface. It should be explained here that if additional levels of similar bracing are required, it can be installed as the rock is excavated downwardly, and also, these levels of horizontal bracing may be tied together by diagonal bracing in the vertical planes. In this connection, if lower levels of bracing are required, the sand packing around the temporary supports may be relied upon to provide sufficient lateral support for the temporary supports, until the lower levels of bracing are installed.

The temporary street decking, as previously indicated, is required to cover over the entire subway excavation. This decking must carry the heavy vehicular as Well as pedestrian traffic and therefore must be of a very substantial character.

For reasons of simplicity and'economy and in order to' obtain a. safe structure and one which will offer the least amount of obstruction to the subway construction, I have associated or combined the previously described system of temporary supports for the existing elevated railroad structure with the temporary street decking system in the following manner:

Laterally opposite the temporary supports 3' and on both sides of the street, I provide additional supports 3" which are placed and treated in the same manner and. are otherwise practically the same, as the temporary supports 3. They do not, of course, extend above the street surface as do the temporary supports 3'. additional supports 3 are connected together and braced, by the longitudinal girders 3| which are set at the same level as the longitudinal brac- These the decking supports 3" are connected together by the transverse bracing beams 30.

Transversely of the longitudinal girders 26 and 3| I now install the steel floor beams 28. These floor beams take their bracings upon said girders 26 and 3| and are properly connected thereto and are also properly tied together. Upon the top lengths can, when required and permitted, be

lifted up so as to provide an adequate hatch Way in said decking, through which materials may be taken out or put into the workings.

,It will of course be understood that, since I have combined the temporary street decking system with the system .of temporary supports for the existing elevated railroad structure, the

supports 3' and the longitudinal bracing members 3! will be properly proportioned to carry the additional load of said decking system.

The decking supports 3' are put in place prior to and independent of the subway construction work and otherwise treated in the same manner as were the temporary supports 3'. Therefore, the advantages that were pointed out concerning said temporary supports are equally true concerning said decking supports and need not be repeated.

The foregoing may be summed up by stating that, now the entire street surface, over the subway, is provided with the required temporaryv decking system, upon which the usual traflic can be maintained and that said decking shall remain in place, undisturbed until the completion of the subway work, we may now therefore, proceed with the subway work.

All of the earth 6, lying between the street surface! and the top of rock 5 is first excavated. In this zone usually is found all the various pipes, sewers and ducts, etc., and of course, these must all be safely supported and maintained. It must be evident that, with a substantial decking system such as previously described, just overhead, that is, just above these various services, it will be most convenient and altogether safe and practicable to suspend these services from the flanges of the floor beams 28. This can be done in a very positive and substantial manner by means of metal collars, saddles, clamps and threaded rods and the like. Since said decking will not be disturbed, neither will these services, if suspended from said decking, be-disturbed until the completion of the subway work.

Now, all excavation, including rock excavation may proceed with dispatch. When the excavation has been completed to the subgrade 356, the fioor or invert 35b of the subway is poured. This invert is usually of concrete. The side walls 350: and the roof 35 are usually'of steel beams and concrete arches. The steel is first set and then the concrete follows.

As the subway structure is being completed there will be places where the temporary supports 3 and also the decking supports 3" pass through the roof of the subway. In fact, practicallyallof these supports will pass through the subway roof. The decking supports are finally removed near the completion of the work. At this time, portions of the decking is being emoved and the street is being backfilled over the roof of the subway. At such times, these decking supports 3" are no longer of service and may be disconnected and removed. The hole that was left in the subway roof to accommodate said support is concreted and backfilling completed.

As to the final treatment of the temporary supports 3, when the subway roof steel in the immediate vicinity of one of said supports is in place then structural plates 33 and angles 33' are fitted and riveted to said support to provide a proper foundation for the support upon the subway roof. The load on the temporary support is then transferred through this new foundation to the subway roof, and of course,. the original foundation of this support, at the bottom of pit i8, is thereby relieved of its load. When this has been accomplished, that portion of the temporary support 3, below the roof of the subin and the street back filled. It is important to note here that in making the conversion. the existing elevated railroad is not in any way disturbed.

Thus the temporary support 3', that is, the upper portion thereof has been converted into a permanent support for the existing elevated structure, resting upon the roof of the new subway which is designed to take this concentrated load. Also, it should be noted, that with the removal of the lower portions of the temporary support the subway train way is cleared of this obstruction.

It will of course be understood that all of the various operations are carried on as a single project but progressively, following each other practically in the order outlined above and in the most economical manner. As the work is completed, the decking is removed, the various supports disposed of or treated as above indicated, the bracing girders removed, the street backfilled, at the same time restoring the pipes and sewers and ducts, etc., and finally, the street pavement restored.

There are many advantages that fiow from the construction and method contemplated by the present invention. It is a system properly designed as distinguished from the present method of working out the problem in the field. It is therefore safe, stable, positive and most economical both in materials and labor. It is all in place prior to and independent of the subway construction and all its parts are proportioned and disposed so as to present a minimum of-interference in the work. 'It provides completely for the safe support of not only the existing elevated railroad structure but also the street trafiic and all pipes, sewers and the like. Also, it provides for permanent support of the emsting elevated railroad structure upon the completion of the work and in most simple, economicaland satisfactory manner.

In other words, the entire subway construction problem has hereby been simplified and all uncertainty and risk practically eliminated. Construction work may proceed in practically a clear area, by the most economical methods. and mod ern tools and with ordinary workmen, all of which results in a large saving in cost and in the time required to complete the subway.

What I claim is:

1. The method of supporting a structure during the excavation of rock from beneath the same which includes forming a pit beneath the structure to a point below the lower level of the proposed excavation, placing a column in said pit, attaching the column to the elevated structure and to the bottom of the pit, supporting the column between its ends by braces between the wall of the pit and the column, and encasing a portion of the column in a shock-buifer material. 2. The method of supporting a structure during the excavation of rock from beneath the same, which includes forming a series of pits beneath the structure to points below the lower level of the proposed excavation, placing a column in each of said pits, attaching each column to the structure and to the bottom of the corresponding pit, bracing each column against lateral deformation against the wall of the corresponding pit and bracing the columns by beams extending between and attached to the columns at a. level above the level of the rock.

3. The method of laying a subway through rock beneath a structure that is normally supported by a series of longitudinallyand transversely arranged columns above the rock, which includes progressively supporting the said structure on each side of each column, progressively removing each column, forming a' series of pits below the elevated structure that extend through the rock to a point below the lowermost level of the proposed subway, progressively placing columns in the pits and attaching the same to the structure and to the rock at the bottom of the pits, bracing each column within the pit against lateral deformation, encasing each column in a shock-buffer material, bracing the columns by means of beams extending transversely and longitudinally between the columns above the surface of the rock, removing the rock to a depth above the points of support of the columns, progressively supporting the buffer material as the rock is removed, laying the subway within the excavation, supporting each column on the roof of the subway and removing the portion of each column below the roof of the subway.

4. The method of laying a subway through rock beneath a structure that is normally supported by a series of longitudinally and transversely arranged columns above the rock, which includes supporting the structure on each side of each column, removing each column, forming a series of pits below the structure that extend through the rock to a point below the lowermost level of the proposed subway, placing columns in each pit and attaching the'same to the structure and to the rock at the bottom of the pit, bracing each column .within the pit against lateral deformation, bracing the columns by means of beams extending "transversely and longitudinally between the columns and above the surface of the rock, removing the rock to a depth above the points of support of the columns, laying the subway within the excavation, supporting each column on the roof of the subway and removing theportion of each column below the roof of the subway.

5. The method of laying a subway through rock beneath a structure that is normally supported by a series of longitudinally and transversely arranged columns above the rock, which includes progressively supporting the structure on opposite sides of transverse pairs of said columns, progressively removing said pairs of columns, progressively creating pits in vertical alignment with the former positions of the removed columns to points below the lower level of the proposed subway, progressively placing columns in said pits and securing them to the structure and the bottoms of the pits, connecting the last mentioned columns with longitudinal and transverse girders above the upper level of the rock, laying a decking upon the said girders, removing the rock from beneath the decking to the lower level of the proposed subway, laying the subway roof, walls and invert, supporting the last mentioned columns on the subway roof, removing the portions of said columns below the subway roof, and removing the longitudinal and transverse girders and decking.

6. The method of laying a subway through rock beneath a structure that is normally supported by a series of longitudinally and transversely arranged columns above the rock, which includes progressively supporting the structure on opposite sides of transverse pairs of said columns, progressively removing the columns so supported, progressively creating pits in vertical alignment with the former positions of the removed columns to points below the lower level of the proposed subway, progressively placing columns in said pits and securing them to the structure and the bottoms of the pits surrounding the portions of the columns within thepits with a shock absorbent material, bracing the last mentioned columns between their ends and within the pits, connecting the last mentioned columns with longitudinal and transverse girders above the upper level of the rock, laying a decking upon said girders, removing the rock from beneath the decking to the lower level of the proposed subway, removing the braces within the pits, laying the subway roof, walls and invert, supporting the last mentioned columns on the subway roof, removing the portions of said columns below the subway roof, and removing the longitudinal and transverse girders and decking.

'7. The method of laying a subway through rock beneath a structure that is normally supported by a series of longitudinally and transversely arranged columns above the rock, which includes progressively supporting the structure on opposite sides of transverse pairs of said columns, progressively removing said pairs of columns, progressively creating pits in vertical alignment with the former positions of the removed columns to points below the lower level of the proposed subway, progressively placing columns in said pits and securing them to the structure and the bottoms of the pits, connecting the last mentioned columns with longitudinal and transverse girders above the upper level of the rock, laying a decking upon said girders, creating pits laterally of and spaced from the aforementioned pits, placing columns in said pits and securing them to the bottoms thereof, connecting the last mentioned columns together and to the first placed columns by girders, extending the decking over the last mentioned girders, removing the rock from beneath the decking to the lower level of the proposed subway, laying the subway roof, walls and invert, supporting the first placed columns on the 'subway roof, removing the portions of said columns below the subway roof, and removing the longitudinal and transverse girders and decking.

8. The method of constructing a subway through rock and of supporting an existing structure that is normally supported by columns having sustaining footings, which includes forming pits in the rock to points adjacent the lowermost level of the proposed subway; placing columns in said pits with footings adjacent the lower ends thereof and transferring the load from the footings of the-first mentioned columns to the second mentioned columns prior to the excavation of proposed excavation, placing a column in said pit the rock for the subway; excavating the rock; constructing a subway structure and thereafter transferring the load of' the second mentioned columns to the subway structure.

9. The method of constructing a subway through rock and of supporting an existing structure that is normally supported by columns having sustaining footings, which includes forming pits in the rock to points adjacent the lowermost level of the proposed subway; placing columns in said pits with footings adjacent the lower ends thereof, placing a shock buffer material around said columns, and transferring the load from the footings of the first mentioned columns to the second mentioned columns prior to the excavation of the vrock for the subway; excavating the rock; constructing a subway structure and thereafter transferring the load of the second mentioned columns to the subway structure.

10. The method of constructing a subway through rock and of supporting an existing structure that is normally supported by columns having sustaining footings which includes forming pits in the rock to points adjacent the lowermost level of the proposed subway; placing columns in said pits with footings adjacent the lower ends thereof, transferring the load from the footings of the first mentioned columns to the second mentioned columns, extending girders transversely and longitudinally between and attaching the same to the second mentioned columns above the level of the rock prior to the excavation of the rock for the subway; excavating the rock; conconstructing a subway structure and thereafter transferring the load of the second mentioned columns to the subway structure.

11. The method of constructing a subway through rock and of supporting an existing structure that is, normally supported by columns having sustaining footings, which includes forming pits in the rock to points adjacent the lowermost level of the proposed subway; placing columns in said pits with footings adjacent the lower ends thereof, transferring the load from the footings of the first mentioned columns to the second mentioned columns, extending girders transversely and longitudinally between and attaching the same to the second mentioned columns, above the level of the rock, supporting a street decking on said girders, prior to the excavation of the rock for the subway; excavating the rock: constructing a subway structure and thereafter transferring the load of the second mentioned.

columns to the subway structure.

12. The method of supporting an existing structure that is normally supported by a longitudinal series of transverse pairs of columns having sustaining footings without disturbing the structure during the removal of rock from beneath the structure, which includes placing temporary support for the structure adjacent the successive pairs of columns, transferring the weight of the structure from the adjacent colum ns to the temporary support; removing said columns; establishing foundations in the rock adjacent the lowermost level of the proposed rock removal, placing columns on said foundations and transferring the weight of the structure from which a subway, involving rock excavation, is to be constructed, which includes placing false work beneath the existing structure to relieve the support of its load, removing said existing support, forming a pit below the existing structure; in-

stalling a new support in said pit substantially in vertical alignment with the position of existing support before its removal, establishing a foundation for said new support at the bottom of said pit below the subgrade of the subway, attaching said new support to said existing structure, removing said false work and thus transferring the load of the existing structure to said new support prior to performing the excavation for the subway, performing said excavation for and constructing said subway.

15. The method of supporting an existing structure having supports generally disposed longitudinally and transversely thereof, beneath which a sub-way involving rock excavation, is to be constructed, which includes placing false work beneath the existing'structure to relieve the support afiected of its load, removing said existing support, forming a pit below the existing structure, installing a new support within said pit substantially in vertical alignment with the position of existing support before its removal, establishing a foundation for said new support at the bottom of said pit adjacent the subgrade of the subway, placing a casing within the rock portion of said pit and filling the same with a shock buffer material to completely surround said new support, attaching said new support to said existing structure, removing said false work and thus transferring the load of the existing structure to said new support prior to performing the excavation for the subway, performing said excavation for and constructing said subway, providing a permanent foundation for said new support upon the completed portion of said subway, and-transferring its load,thereby to said subway and removing the portions of said new support below said permanent foundation.

16. The method of supporting an existing structure arranged above a street and having supports generally disposed longitudinally and transversely thereof, beneath which a subway, involving rock excavation, is to be constructed and of providing a temporary street surface, which includes progressively relieving the existing supports of their loads, progressively removing said existing supports, progressively forming pits below said existing structure substantially in vertical alignment with the position of said existing supports before their removal, prbgres sively installing new supports, each within one of said pits and providing lateral clearance all around said supports within the rock portion of said pits, progressively establishing a foundation for each of said new supports on the bottom of their respective pits adjacent the subgrade of the subway, progressively attaching each of said new supports to said existing structure, progressive- 1y transferring the load of the existing structure to the new supports prior to performing the excavation of the subway, removing the street surface and beginning said subway excavation and simultaneously therewith and progressively installing longitudinal and transverse structural bracing atapproximately the street level to form a system of supports for a temporary street decking, progressively laying said temporary street decking upon said structural bracing, performing a general excavation for and constructing the subway structure beneath said temporary street decking and removing said street decking and said longitudinal and transverse structural bracing.

17. The method of supporting an existing structure arranged above a street and having supports generally disposed longitudinally and transversely thereof, beneath which a subway, involving rock excavation, is to be constructed, and of providing a temporary street surface which includes progressively relieving the existing supports of their loads, progressively remov ing said existing supports, progressively forming pits below said existing structure substantially in vertical alignment with the position of said existing supports before their removal, progressively installing new supports, each within one of said pits and providing lateral clearance all around said supports within the rock portion of said pits, progressively establishing a foundation for each of said new supports on the bottom of their respective pits adjacent the subgrade of the subway, progressively attaching each of said new supports to said existing structure, progressively transferring the load of the existing structure to' the new supports prior to performing the excavation of the subway, removing the street surface and beginning said subway excavation and simultaneously therewith and progressively installing longitudinal and transverse structural bracing at approximately the street level to form a system of supports for a temporary street decking, progressively laying said temporary street decking upon said structural bracing, performing a general excavation for and constructing the subway structure beneath said temporary street decking, establishing permanent foundations for said new supports upon the finished portions of the subway structure and connecting the same to said new supports structure that is normally supported by columns having sustaining footings, forming pits in the rock to points adjacent the lowermost level of the proposed subway, placing columns in said pits with footings adjacent the lower ends thereof and transferring the load from the footings of the first mentioned columns to the second mentioned columns prior to the excavation of the rock for the subway; excavating the rock; and constructing a subway structure.

19. In the method of constructing a subway through rock and of supporting an existing structure that is normally supported by columns having sustaining footings, forming pits in the rock to points adjacent the lowermost level of the proposed subway, placing columns in said pits with footings adjacent the lower ends thereof, placing a shock buffer material around said columns, and transferring the load from the footings of the first mentioned columns to the second mentioned columns prior to the excavation of the rock for the'subway; excavating the rock; and constructing a subway structure.

20. In the method of constructing a subway through rock and of supporting an existing structure that is normally supported by columns having sustaining footings, forming pits in the rock to points adjacent the lowermost level of the proposed subway; placing columns in said pits with footings adjacent the lower ends thereof and transferring the load from the footings of the first mentioned column to the second mentioned columns; forming pits in the rock'laterally of the first mentioned pits, placing columns in said pits, tieing all of said columns together by longitudinal and transverse girders, and placing a street decking'on said girders both beneath and laterally of the said existing structure prior to the excavation of the rock for the subway and excavating the rock.

WALTER CACCIA.

DISCLAIMER 2,059,774.-Walter Cassia, White Plains, N. Y. METHOD OF OONSTRUCTING SUB- WAYS. Patent dated November 3, 1936. Disclaimer filed May 7, 1940,

by the assignee, John H. Unlandherm. Hereby enters this disclaimer to claims 1, 8, 9, 10, 12, 13, 14, 15, 18, and 19 of said specification.

[Ofiicial Gazette May 28, 1940.] 

